The present invention relates to an easily openable sealed package bag that can suitably be opened by breaking open a package film as a packaging material with a finger tip and also to an apparatus for manufacturing the easily openable sealed package bags.
A package bag has conventionally been made by vertically or laterally sealing three or four sides of a package film made of a packaging material, such as a synthetic resin film or a laminated material formed by laminating the synthetic resin film and an aluminum foil or the like. The package bag is filled with a material to be packed, such as liquids, powders or viscous materials, before being hermetically sealed.
To open the package bag, therefore, it is common practice to cut a sealed portion of the package film as the packaging material with a knife or scissors or break it open with a finger tip. When the package bag is to be cut with a knife or scissors, the opening procedure is troublesome as it requires a tool. When the package film is to be ruptured with a finger tip, the opening of the package film may not be accomplished easily.
For these reasons, the package bag has recently been formed with a seal opening notch, which comprises a cut, at a sealed portion of the package bag to make it easy to break open the package bag. Two types of opening notch are employed in general. For example, as shown in FIG. 12, a package bag P with its three sides sealed is formed with a simple cut or a so-called I-notch N1 at a sealed portion S. Alternatively, as shown in FIG. 13, a package bag P with its four sides sealed is formed with a so-called V-notch N2, which is formed by making a V-shaped cut, at a sealed portion S. The opening notch is formed in the package bag P in this way.
In making an opening notch, although the I-notch N1 offers the advantage of simple manufacturing because of a simple shape of the cut, there is a drawback that, because the I-notch N1 is formed by making a simple cut at the sealed portion S of the package bag P, the edge portion of the opening I-notch N1 is aligned with the side of the bag and may not be recognized easily, making it difficult to quickly locate the position of the I-notch N1.
In this respect, the V-notch N2 which is a V-shaped cut is easily recognized because of its shape even by a person with failed eyesight. The use of the V-notch as an opening notch however is currently not applied to food product packages in which materials W to be filled in the package bag P are foods such as sauce, soup and soy sauce, because when the V-notch N2 is to be formed in the sealed portion S of the package bag P, the sealed portion S of the package bag P needs to be cut in the shape of letter V during the notch forming process, producing cut chips which in turn may adhere to the product package bag P.
It is therefore an object of the invention to provide an easily openable sealed package bag which can improve the level of ease with which the package bag can be opened, without producing cut chips of the package bag, and which can enhance the level of ease with which the opening portion can be located with sight or feel. It is also an object of the invention to provide an apparatus for manufacturing such an easily openable sealed package bag.
In a package bag that hermetically seals a material to be packed, such as liquid, powder and viscous material, by longitudinally and laterally sealing three or four sides of a package film, the package according to the invention is characterized by: a seal opening notch comprising a cut formed in a sealed portion of the package bag in such a manner as to extend in a direction of depth of the sealed portion; and a bent portion formed in the sealed portion adjacent to the seal opening notch comprising a cut. A resulting step formed by the bent portion allows the user to identify a seal opening notch position easily.
Further, the sealed portion of the package bag is formed with a seal opening notch comprising a cut which extends in a direction of depth of the sealed portion, and also with a bent portion (stepped portion) which extends from the deepest part of the seal opening notch comprising a cut toward an outer edge of the sealed portion. This structure easily forms a step at the edge portion where the notch is cut, making it possible to easily locate the notch portion comprising a cut. Further, the configuration comprising the seal opening notch and the bent portion (stepped portion) easily forms, by bending, a step with an almost V- or U-shaped width, thereby improving the ease with which the seal opening notch position can be distinguished by sight as well as by touch.
Further, in a packaging machine that continuously makes package bags, the apparatus is characterized in that a notch forming mechanism is provided which has a pair of opposing rolls for clamping and transporting the longitudinally sealed portion of the continuously fed package bags; and that a circumferential surface of at least one of the opposing rolls is formed with a protruding cutting edge that makes a seal opening notch comprising a cut in the longitudinally sealed portion of the package bags in such a way that the seal opening notch extends in a direction of depth of the longitudinally sealed portion, with the other roll functioning as a receiving roll, and the circumferential surface is also formed with a protruding bending edge that forms a bent portion in the longitudinally sealed portion adjacent to the seal opening notch. This construction provides an apparatus for manufacturing easily openable sealed package bags that allow the user to identify the seal opening portion while preventing cut chips from being produced as a result of making notches.
Further, in a packaging machine that continuously makes package bags, the apparatus is characterized in that a notch forming mechanism is provided which has a pair of opposing rolls for clamping and transporting the longitudinally sealed portion of the continuously fed package bags; that a circumferential surface of at least one of the opposing rolls is formed with a protruding cutting edge that makes a seal opening notch comprising a cut in the longitudinally sealed portion of the package bags in such a way that the seal opening notch extends in a direction of depth of the longitudinally sealed portion, with the other roll functioning as a receiving roll, and the circumferential surface is also formed with a protruding bending edge that extends continuously from the cutting edge at a position corresponding to the deepest part of the seal opening notch toward an outer edge of the longitudinally sealed portion in order to form a bent portion (stepped portion) in the longitudinally sealed portion; and that a height of a tip of the bending edge is set slightly lower than a height of a tip of the cutting edge. This construction provides an apparatus for manufacturing easily openable sealed package bags that allow the user to identify the seal opening portion while preventing cut chips from being produced as a result of making notches.